2001 150 ox66 Alarm when key on, limp mode

[Yamaholic]

Hey rowdy roddybolt. Easy easy. I understand that the ecu doesn't monitor fuel pressure. Think you already told me. Remember that i am just a backyard mechanic, with 20 years of experience with yamaha snowmobiles, snowblowers, motorcycles, waverunners, etc, and i work 9-5 as a professional mechanical engineer. Dont refer to me as dense. I am open to learning this stuff but seems like you might have closed up all your books. Trying to give as much info as i can so that i can get to a solution faster that is all.
That said, just confirmed that all injectors and fuel pump is new. I have changed to a portable tank as well. When I say that this engine goes into rpm reduction, maybe I am not right. But I can guarantee that the ecu or Cdi or something is systematically reducing rpms after I try to accellerate. Anyway, for those who don't agree, how about we agree to disagree.
I just had the boat in the water for a trial and nothing had changed. I did check the #2 and #5 cylinders to see if they were firing at idle and they weren't, which from what I understand is nornal. Anyway, I did check the voltage on the sensor and was getting a low reading while cranking and nothing when running. I tried unplugging the sensor and there was no difference in the engine when idling. I tried it in gear and to wot wit it unplugged, and the engine got the boat up on plane and seemed to run fine. I kept it running on and off plane for about 20 minutes and ran perfect. Anyone care to comment?
I also found out that this engine was just rebuilt by the dealer. How exactly does the cps tell the position of the crank when all the teeth are the same on the ring gear? Is there anything on the inside of the ring gear that causes the signal to become irregular tell where the crank is in its rotation? Any chance the ring gear is not installed in its proper location and is telling the engine false info on the crank position? I don't have that part of the service manual to confirm what the correct position is.
All comments welcome guys.

[99yam40]

Hey rowdy roddybolt. Easy easy. I understand that the ecu doesn't monitor fuel pressure. Think you already told me. Remember that i am just a backyard mechanic, with 20 years of experience with yamaha snowmobiles, snowblowers, motorcycles, waverunners, etc, and i work 9-5 as a professional mechanical engineer. Dont refer to me as dense. I am open to learning this stuff but seems like you might have closed up all your books. Trying to give as much info as i can so that i can get to a solution faster that is all.
That said, just confirmed that all injectors and fuel pump is new. I have changed to a portable tank as well. When I say that this engine goes into rpm reduction, maybe I am not right. But I can guarantee that the ecu or Cdi or something is systematically reducing rpms after I try to accellerate. Anyway, for those who don't agree, how about we agree to disagree.
I just had the boat in the water for a trial and nothing had changed. I did check the #2 and #5 cylinders to see if they were firing at idle and they weren't, which from what I understand is nornal. Anyway, I did check the voltage on the sensor and was getting a low reading while cranking and nothing when running. I tried unplugging the sensor and there was no difference in the engine when idling. I tried it in gear and to wot wit it unplugged, and the engine got the boat up on plane and seemed to run fine. I kept it running on and off plane for about 20 minutes and ran perfect. Anyone care to comment?
I also found out that this engine was just rebuilt by the dealer. How exactly does the cps tell the position of the crank when all the teeth are the same on the ring gear? Is there anything on the inside of the ring gear that causes the signal to become irregular tell where the crank is in its rotation? Any chance the ring gear is not installed in its proper location and is telling the engine false info on the crank position? I don't have that part of the service manual to confirm what the correct position is.
All comments welcome guys.

What sensor are you unplugging?
What voltage are you reading?

Have you checked timing to see what it is doing?
What about fuel pressures?
have you made sure all plugs were sparking?

Seems testing while problem is there and when you unplug what ever you are unplugging would show something that is changing

[rodbolt17]

an anganeer.
that splains it.

there is one tooth slightly different, that's why the air gap is rather important.
it tracks the phase angle of the crank.

the OX 66 version does not kill spark like the HPDI version or the 3.1L OX66.
if your losing spark its a CDI,pulser coil or wiring issue.
like I said if the alarm audible works, any thing that will place it in RPM reduction will sound that audible.
failure of the CPS wont affect spark.
it will fix timing at 7*BTDC and idle speed will increase and fuel will be fixed.
but all six will spark.

what is fuel rail pressure at the failure RPM and load ?

[Yamaholic]

99yam40, it was the crank pos sensor. I know you guys keep talking about fuel rail pressure but I was kinda on the way to thinking that since I had this engine running the boat for 20 min at 3/4 to wot, the fuel pressure is just fine? Or am I again missing something?
I will check the cps voltages again while in the yard as it is easier to do there. Was hoping that either the cps or an incorrectly installed flywheel might be the culprit. Not even sure if you can install the flywheel incorrectly, assuming it is keyed. Anyway, at least I have an engine that works now, or almost.
Also, what do you guys use to check fuel rail pressure? I see a test port there.
Thanks again.

[rodbolt17]

as an engineer your still missing it, as most angaaneers do.
yep my da was one too.

any time rail pressure falls engine performance suffurs.
any time rail pressure passes about 45 PSI on that engine,clogged regulator filter, performance suffers.

can you not grasp the simple concept that the faster that engine spins up, UNDER a load NOT in the freaking driveway, the MORE gas it MUST consume at the SAME pressure.

speed density EFI has been around for at least 30 years.

it aint changed much.
don't care if we are discussing an OX 66 or my old 87 2500 series 4x4 chebby.
both worked EXACTLY the same.

its not the CPS, unless you have already dinked with the throttle stop screw.

if the CPS signal is incorrect or unplugged ign timing will default to 7*BTDC and idle speed will increase to about 1100 RPM.

while stupid the ECU will react to a signal loss.

but again the ecu DOES NOT and CANNOT monitor fuel.

why I dunno.
ask some dumbass anageer why the MOST critical part of the system isn't monitored.
I don't engineer nor design them.
I have spent about 30 years simply fixing them.
you spend 20 min at 3/4 throttle, at min 21 rail pressure goes low.
at min 21 your engine RPM declines.
the ONLY way to test this system is by eliminating spark compression and fuel.
however fuel MUST be tested at the RPM and LOAD failure.

[Yamaholic]

as an engineer your still missing it, as most angaaneers do. MAN, YOU REALLY HAVE IT IN FOR ENGINEERS. GOOD THING WE AREN'T THAT ANGRY WITH MECHANICS.
yep my da was one too.

any time rail pressure falls engine performance suffurs.
any time rail pressure passes about 45 PSI on that engine,clogged regulator filter, performance suffers.

can you not grasp the simple concept that the faster that engine spins up, UNDER a load NOT in the freaking driveway, the MORE gas it MUST consume at the SAME pressure. AS I HAVE TOLD YOU, THE ENGINE RUNS FINE UNDER LOAD WITH THE CPS UNPLUGGED SO I THINK THE FUEL ISSUE IS OK???
I do understand that the load requires more fuel.

Just find it hard to believe that if the engine works fine(other than it may not be optimally tuned for timing) with the cps unplugged, why would I have a fuel rail pressure problem? does that not rule it out? the engine will run fine all day with the cps unplugged. If rail pressure was the issue, would it not still be an issue with the cps uplugged? new fuel pump and filters are all clean.


Anyone care to comment on the other questions I had, like if the flywheel can be installed at the incorrect position?
how do you check fuel rail pressure? ie, what do you use to check? looks like a regular tire valve port.
also, what is the gap between the cps and the flywheel teeth? this would have an effect on the voltage.

[TownsendsFJR1300]

Not knowing the exact engine model #, but the flywheel is indeed keyed (installed only in ONE POSITION);

Part #8

http://www.boats.net/parts/search/Ya...TOR/parts.html



Woodruff keys can shear, not likely, but possible

[Yamaholic]

thanks townsendsFJR. finally some feedback without any degrading/insulting comments. figured it would be something like that or a spline. have a great day.

[boscoe99]

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[99yam40]

either get a service manual for your motor and follow the steps for testing things with the proper test equipment or take it to someone that can.

Just thinking something is OK does not get it done, make sure it is in spec

[TownsendsFJR1300]

thanks townsendsFJR. finally some feedback without any degrading/insulting comments. figured it would be something like that or a spline. have a great day.

You welcome..

If I knew more (not experianced in what your issues are) I would post.

Boscoe is also very knowledgable and generally doesn't bite!

Good luck!

[ausnoelm]

As a general rule, rodbolt doesn't bite either, IF you follow his advice and do what is asked, instead of jumping from place to place and STILL not testing what was asked, if I was him, and knew what he does, I would be biting a lot harder, I can tell you.

[boscoe99]

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[TownsendsFJR1300]

Agreed 100%^^^

IMO, Name calling, demeaning statements doesn't solve a thing.

There's absolutly NO reason for it.

If it bothers someone that much, perhaps its best they don't respond at all..

[99yam40]

asking someone to test something and not having it done,
and then they keep asking for help should mean not responding back.

But I keep asking to see if they will do it even if I did not ask the 1st time myself. Just prodding them along.


I cannot understand why anyone, especially an self proclaimed educated person, would go this far without testing anything or having a service manual for the motor they were working on so they have access to the info